linux/kernel/gen_kheaders.sh
Masahiro Yamada ea79e5168b kheaders: optimize header copy for in-tree builds
This script copies headers by the cpio command twice; first from
srctree, and then from objtree. However, when we building in-tree,
we know the srctree and the objtree are the same. That is, all the
headers copied by the first cpio are overwritten by the second one.

Skip the first cpio when we are building in-tree.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-11-11 20:10:01 +09:00

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#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
# This script generates an archive consisting of kernel headers
# for CONFIG_IKHEADERS.
set -e
sfile="$(readlink -f "$0")"
outdir="$(pwd)"
tarfile=$1
cpio_dir=$outdir/$tarfile.tmp
dir_list="
include/
arch/$SRCARCH/include/
"
# Support incremental builds by skipping archive generation
# if timestamps of files being archived are not changed.
# This block is useful for debugging the incremental builds.
# Uncomment it for debugging.
# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
all_dirs=
if [ "$building_out_of_srctree" ]; then
for d in $dir_list; do
all_dirs="$all_dirs $srctree/$d"
done
fi
all_dirs="$all_dirs $dir_list"
# include/generated/compile.h is ignored because it is touched even when none
# of the source files changed. This causes pointless regeneration, so let us
# ignore them for md5 calculation.
headers_md5="$(find $all_dirs -name "*.h" |
grep -v "include/generated/compile.h" |
grep -v "include/generated/autoconf.h" |
xargs ls -l | md5sum | cut -d ' ' -f1)"
# Any changes to this script will also cause a rebuild of the archive.
this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
if [ -f kernel/kheaders.md5 ] &&
[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
exit
fi
if [ "${quiet}" != "silent_" ]; then
echo " GEN $tarfile"
fi
rm -rf $cpio_dir
mkdir $cpio_dir
if [ "$building_out_of_srctree" ]; then
pushd $srctree > /dev/null
for f in $dir_list
do find "$f" -name "*.h";
done | cpio --quiet -pd $cpio_dir
popd > /dev/null
fi
# The second CPIO can complain if files already exist which can happen with out
# of tree builds having stale headers in srctree. Just silence CPIO for now.
for f in $dir_list;
do find "$f" -name "*.h";
done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
# Remove comments except SDPX lines
find $cpio_dir -type f -print0 |
xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
# Create archive and try to normalize metadata for reproducibility.
# For compatibility with older versions of tar, files are fed to tar
# pre-sorted, as --sort=name might not be available.
find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
--owner=0 --group=0 --numeric-owner --no-recursion \
-Jcf $tarfile -C $cpio_dir/ -T - > /dev/null
echo $headers_md5 > kernel/kheaders.md5
echo "$this_file_md5" >> kernel/kheaders.md5
echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
rm -rf $cpio_dir